Conveyor belt

ABSTRACT

A conveyor belt is adapted in endless design to follow, through a part of its length, a path comprising a number of superimposed, helically extending tiers. The conveyor belt consists of mutually articulated and relatively adjustable links, each comprising a bottom part and spacers arranged at the longitudinal edges of the bottom part, the spacers forming the two sides of the belt, the upper edge portions of the spacers being adapted to engage the lower edge portions of overlying tiers of the conveyor belt and fixedly connected through a part of their length to the longitudinal edges of the bottom part, the remaining part being movable relative to the bottom part. Each spacer is provided with shoulders mutually displaced in both the longitudinal direction and the lateral direction of the belt, to engage with both the inner side and the outer side of the an upper edge portion of the spacer of the underlying belt tier, thereby to positively guide the edge portion in the lateral direction.

The present invention relates to a conveyor belt which is adapted inendless design to follow, through part of its length, a path comprisinga number or superimposed, helically extending tiers forming a belt pile.

Such a conveyor belt is previously known from SE patent No. 381,241 andSE patent application No. 8206760-4 and consists of mutually articulatedand relatively adjustable link means, each comprising a bottom part andspacer means arranged at the longitudinal edges of said bottom part,said spacer means forming the two sides of the belt and being adapted,with their upper edge portions, to bear against the lower edge portionsof the overlying tier of the conveyor belt. In this manner, each belttier is supported by an underlying belt tier and supports itself anoverlying belt tier.

In order to prevent relative lateral displacement of the superimposedbelt tiers, at least a part of the spacer means according to the SEpatent are adapted to engage shoulders at the lower edge portions ofsaid spacer members on at least one side of the overlying tier of theconveyor belt.

According to SE patent application No. 8206760-4, the spacer meansthrough part of their length are fixedly connected to the longitudinaledges of the bottom part, while the remaining part is movable relativeto the bottom part and provided with a flange which is inclined downwardand inward, i.e. toward the center of the belt, said flange forming,together with the flanges of adjacent spacer means, shoulders with whichthe upper edge portions of the spacer means on the underlying belt tierare adapted to engage to prevent relative lateral displacement of thebelt tiers.

If it is attempted to increase the eight of the belt pile or to increasethe width or height of the link means, and thus the width or height ofeach tier, the above conveyor belt constructions constitute an obstaclein so far as the risk that the belt pile may collapse will quicklyexceed permissible limits. Although higher strength and rigidity may beobtained by increasing the dimensions of the parts included in the linkmeans, this will also increase the weight of the conveyor belt,resulting in such an increased load on the bottom tier of the belt pilethat the entire belt pile tends to collapse.

It therefore is the object of the present invention to make it possibleto increase the dimensions of both the conveyor belt and the belt pilewithout causing the risk of a collapse to exceed a safe limit.

The construction according to the invention precludes any possibility ofan undesired lateral relative displacement of the belt tiers in the beltpile, and this is accomplished by the mutual positive guiding in thelateral direction between the spacer means in superimposed belt tiers.

More particularly, the present invention pays regard to the fact thatone important cause of a collapse is the tensile force which isgenerated in the conveyor belt by the friction in the return path fromthe point where the belt leaves the belt pile to the point where itreenters the pile. The tensile force strives to contract the lowermostbelt tier which, however, normally is held in position by an internalsupporting ring. In the prior art conveyor belts, the tensile force mustthen be absorbed completely by the first belt tier free from thesupporting ring.

The conveyor belt construction according to the invention makes the beltpile act essentially as a single stable drum which thus is able, viaseveral belt tiers, to absorb the belt tension caused by said tensileforce and to effectively prevent contraction of the belt pileimmediately above the supporting ring.

By the construction according to the invention, the link meanspositioned in superimposed belt tiers will be firmly interengaged, atleast on the outer side of the belt pile, in contrast to the looseinterengagement of the prior art constructions. In this manner, thestrength of the belt pile could be increased many times over.

The considerable increase in strength can be utilised for selectingthinner and thus lighter materials for the link means and/or for givingthe total belt pile a size that would be impossible under othercircumstances.

Furthermore, the invention makes it possible to use the same basicmaterial, i.e. in respect of thickness, for manufacturing the componentsof the link means, irrespective of the width and height of the belt andthe number of tiers in the pile, and this is a considerable advantagefrom the viewpoint of manufacture.

The invention will be described in more detail hereinafter, referencebeing had to the accompanying drawings.

FIG. 1 is a perspective view of a conveying device for which theconveyor belt according to the invention is intended.

FIG. 2 is a schematic cross-sectional view of the link means of two belttiers, and

FIG. 3 shows a part of the conveyor belt from above.

FIG. 4 is a lateral view of an embodiment of a spacer means according tothe invention.

FIGS. 5 and 6 show the spacer means in FIG. 4 as seen in thelongitudinal direction of the conveyor belt and from below,respectively.

FIG. 7 is a view, corresponding to FIG. 4, of a second embodiment of aspacer means according to the invention

FIG. 8a illustrates schematically the deformation of link means adjacenta supporting ring.

An endless conveyor belt 1 intended, for example, for a conveying deviceof the type illustrated in FIG. 1 is adapted to follow, in the mannerillustrated, through part of its length a path comprising a number ofsuperimposed helically extending tiers. The conveyor belt 1, partiallyillustrated in FIGS. 2 and 3, comprises a number of mutually articulatedand relatively adjustable link means consisting of a bottom part 2 and,disposed at the ends thereof, links 3 which form the two sides of theconveyor belt and, at the same time, are designed as spacer means, theupper edge portions 4 of which bear against the lower edge portions ofthe spacer means of the overlying belt tier and thus support theoverlying belt tier via the respective edge portions.

In the embodiment illustrated, the bottom part 2 consists of transverserod-shaped connecting elements 5 for the links 3. These connectingelements 5 may be coated with wire, netting or the like to serve as asupporting plane and permit adjustment of the link means by mutualdisplacement thereof in the longitudinal direction of the belt 1.

The spacer means or links 3 are through a part 6 of their length fixedlyconnected to the longitudinal edges of the bottom part 2. In theembodiment illustrated, this is achieved in that they are fixedlyconnected with two of the rod-shaped elements 5 which are spaced apartin the longitudinal direction of the belt. The remaining part 7 of thespacer means 3, which extends in the longitudinal direction beyond thesaid two rod-shaped elements 5, is movable relative to the bottom part 2and provided with downwardly and inwardly inclined flange 8. The flanges8 of the successive spacer means 3 form inner shoulders engaging theinner side of the upper edge portion 4 of the spacer means 3 of theunderlying belt tier. According to the invention, the lower portion 9 ofthe part 6 is inclined in a downward and outward direction and continuesin a further outwardly angled portion 10 extending essentiallyperpendicular to the belt side. The inclined portions 9 of thesuccessive links 3 thus form outer shoulders engaging the outer side ofthe upper edge portion 4 of the spacer means 3 of the underlying belttier. In this manner, the upper edge portion 4 is positively guided inthe lateral direction between the oppositely directed shoulders formedby the flanges 8 and the inclined portions 9 arranged alternately in thelongitudinal direction of the belt.

To prevent the upper edge portion 4 from being wedged between theoppositely directed shoulders and to give each belt tier a well definedheight, supporting means are fixedly arranged on the inner side of theinclined portions 9 having a supporting surface 11 essentiallyperpendicular to the belt side. The supporting surface 11 is suitablyformed by the bottom part 2 and may preferably consist of the undersideof the rod-shaped elements 5 which, in the embodiment illustrated,extend through holes in the inclined portion 9 to engage with theirouter end the upper side of the portions 10, for example by welding.

The shoulders which, in accordance with the invention, are mutuallydisplaced both in the longitudinal and in the lateral direction of thebelt, make it possible to achieve a positive lateral guiding of theupper edge portion 4 of the underlying spacer means 3, simultaneously asthe belt can move along a curve, as shown in FIG. 3.

Via a transition 12, the part each spacer means 3, which is fixedrelative to the bottom part 2, is slightly laterally displaced relativeto the movable part 7, the part 6 being arranged to overlap on the outerside the part 7 of the adjacent spacer means. The part 7 also has anoblong hole 13 to receive an elongated element associated with anadjacent spacer means, and to facilitate adjustment of the link meansrelative to one another by longitudinal displacement of the part 6 of aspacer means in relation to the part 7 of an adjacent spacer means.

In FIG. 4, the transition between the parts 6 and 7 is straight, but mayalso have the curved shape illustrated at 12' in FIG. 7 where theinclined portion of the part 6' is longer than the flange 8' of the part7'. Furthermore, the part 7' has no oblong hole since the spacer meansaccording to FIG. 7 is suitable for entirely straight belt conveyors orpreferably is arranged in the outer curve when the conveyor travelsthrough a curve. Thus, a spacer means 3' according to FIG. 7 may becombined with the spacer means 3 according to FIGS. 4-6.

The transition 12, 12' contributes to increasing the rigidity of thespacer means 3 and 3', respectively. An increased flexural rigidity inthe connection between the spacer means 3 and the bottom part 2 isachieved by means of a vertical ridge 13 formed in the lower portion ofthe part 6.

To achieve the main part of the effect according to the invention, itsuffices that the spacer means 3 on the outer side of the belt pile areformed in the manner described above, with the shoulders 8, 9 forengagement with both the inner side and the outer side of the upper edgeportion 4 of the spacer means 3 of the underlying belt tier, while thespacer means 3 on the inner side of the belt pile merely require theshoulders 8 for engagement with the inner side (as seen toward thecenter of the belt) of the upper edge portion 4 of the spacer means 3 ofthe underlying belt tier.

The effect provided by the construction according to the invention willappear from FIG. 8. At FIG. 8a, a schematic section radially through twotiers of a conveyor belt according to prior art technique is shown, FIG.8b shows the same section for a conveyor belt according to the presentinvention. It will be evident that, in the conveyor belt according toprior art technique, the load on a belt tier A above a belt tier Bengaging an inner supporting ring S causes a deformation of the linkmeans of the belt tier B, such that the belt pile may collapse becausethe belt tier A partially drops into the belt tier B. The risk of such acollapse is completely eliminated with the conveyor belt according tothe invention where the upper edge portion of the outer link 3 in thebelt tier B is fixedly clamped against the lower edge portion of thelinks of the belt tier A, i.e. between the shoulders 8 and 9 thereof.Practical tests have shown that this fixed clamping actually increasesthe strength of the belt pile by almost a tens power.

A number of modifications of the conveyor belt as described above areconceivable within the scope of the invention. For example, theshoulders 8 and 9 need not be longitudinally displaced relative to oneanother, although such displacement is preferred because it makes itpossible to manufacture the spacer means 3 in a single piece from asimple sheet-metal blank.

I claim:
 1. A conveyor belt which is adapted in endless design tofollow, through a part of its length, a path comprising a number ofsuperimposed, helically extending tiers forming a belt pile, said beltconveyor consisting of mutually articulated and relatively adjustablelink means, each comprising a bottom part (2) and spacer means (3)arranged at the longitudinal edges of said bottom part and forming thetwo sides of the belt, said spacer means being adapted, with their upperedge portions (4), to bear against the lower edge portions of theoverlying tier of the conveyor belt and being fixedly connected, througha part (6) of their length, to the longitudinal edges of said bottompart, and and through the remaining part (7), being movably relative tosaid bottom part, characterized in that each spacer means (3) on theouter side of the belt pile is provided with shoulders (8, 9) mutuallydisplaced in the lateral direction of the belt (1) and, for engagingboth the inner and the outer side of an upper edge portion (4) of thecorresponding spacer means of the underlying belt tier, and thus forpositively guiding this edge portion in both lateral directions betweensaid oppositely directed shoulders, and that each spacer means (3) onthe inner side of the belt tier has at least those shoulders (8) whichare intended to engage the inner side of an upper edge portion (4) ofthe corresponding spacer means of the underlying belt tier, andcharacterised in that the shoulder of the spacer means (3), whichshoulder is intended to engage the inner side of said upper edge portion(4), is formed by a flange (8) which is directed obliquely downwardlyand inwardly from the spacer means part (7) which is movable relative tosaid bottom part (2), and that the shoulder of said spacer means (3),which shoulder is intended to engage the outer side of said upper edgeportion (4), is formed by a lower portion (9) of the spacer means part(6) which is fixed relative to said bottom part (2), said portion (9)being angled obliquely downwardly and outwardly.
 2. A belt conveyor asclaimed in claim 1, characterised by supporting members fixedlyconnected with and extending inwardly from the shoulder (9) engaging theouter side of said edge portion (4), to form a supporting surface (11)adapted to support the spacer means (3) on the said edge portion (4). 3.A belt conveyor as claimed in claim 2, characterised in that the bottompart (2) is formed by rod-shaped elements (5) extending in the lateraldirection of the belt (1) and fixedly connected at each end to that part(6) of a spacer means (3) which is fixed relative to said bottom part,said supporting members comprising a substantially horizontal lower sideof said rod-shaped elements forming the said supporting surface (11). 4.A belt conveyor as claimed in claims 1, characterised in that eachrod-shaped element (5) extends through a hole in the obliquelydownwardly and outwardly angled lower portion (9) of that part of aspacer means (3) which is fixed relative to said bottom part (2), and isfixedly connected to a further outwardly angled portion (10) which formsan extension of said obliquely downwardly and outwardly angled portion(9).